The present invention relates to an improved scriber assembly which is collapsible, allowing it to be easily transported, especially when the main structural components are made of lightweight hollow tubular materials as described in the preferred embodiment.
The operator or passenger in a wheeled vehicle may feel that the operating or ride characteristics of the vehicle are being adversely affected by non-uniformity of the wheels, or tires mounted on the wheels. Although there are many possible causes of non-uniformity in tires and wheels, which are familiar to persons working in the tire and vehicle technology, such causes often are discernible as variations in the distance from the axis of rotation of a wheel to various points on the circumference of the ground-engaging tread portion of the tire mounted on the wheel, hereafter referred to as the radial runout of the wheel and tire assembly. Another common manner of discerning causes of non-uniformity in wheel and tire assemblies mounted on vehicles is a variation in the distance from a circle marked on the sidewall portion of a tire mounted on a vehicle wheel, with the axis of rotation of the wheel being the center of the circle, to a reference point adjacent to the circle but not in the same vertical plane as the circle, with the shortest distance between the reference point and the circle on the sidewall of the tire being measured as the tire and wheel are rotated while the reference point remains in a fixed position, the range of the measurements taken being referred to as the lateral runout of the wheel and tire assembly. While radial and lateral runout measurements are normally small, they sometimes indicate that corrective action should be sought through a tire dealer or a mechanic. While various types of equipment have been developed for checking radial and lateral runout, such equipment is usually bulky, not collapsible, and can be used only in a specialized testing environment such as a professional garage.